I feel your pain. Ideally the standard should have an appendix that explains their rationale for rejecting the hoods. But that really isn't what the standards do. I recently was voted down for including a long appendix in the theatrical fall protection standard (ANSI) which included all the current regulations we had to consider and showed why we had to reject certain equipment. Nope, said the committee, and out it went. Fortunately, being on the committee, I still have access to this incredibly complete regulation list one of the other members put together for my own exploitation.

If you don't like the NFPA standards, $75/year makes you a member, you can apply to be on the committee, and you can raise your voice more effectively. And since it is all done by e-mail, it's inexpensive and kinda fun.

The big problem I have with NFPA documents is that they make big statements without any justification or explanation on why that statement was made.

For the recent case in point, they just state that ductless hoods cannot be used, but not why.

I think the NIH document has a good description of the problems -whether or not you agree with the final decision, I think the document describes the major issues. There must also be changes in ductless technology since that document was done in 2005.

Let's fact it, we are all in the same situation with expanding research programs, a new focus on lab safety and a capacity limited hood system.

At Michigan Tech we have replaced the blower motors with larger motors and changed the pulleys to make the fans spin faster. Maybe even replaced a blower or two. We have also added dampers at various places to level out the load, and even turned off or reduced the airflow to hoods that were not being used or of minimal hazard. This allowed us to add a few hoods, but nothing major.

In my opinion, the hoods in our building are the most precious real-estate we have.

I have a question regarding NFPA 45. I am wondering how undergraduate
research labs fit into the definition of Instructionallaboratory units. As defined in
the 2011 version of NFPA:

"used for educationpast the 12thgrade and before post-college
graduate-level instructionfor thepurposes of instruction of six or more persons for
four or more hours per day or more than 12 hours per week.
Experiments and tests conducted in instructional lab units areunder the direct supervision of an
instructor. Lab units used forgraduate or post-graduate researchare not to be considered
instructional lab units."

The definitionspecificallyexcludesgraduate and post-graduate research. Why doesn't it exclude
"undergrad research" too? This would be situations where the
instructor is not always present, but labs where several undergraduate students
are working at the same time.

Hi everyone:
I was asked by my department
to assist in deciding whether to purchase ductless fumehoods for our
undergraduate chemistry labs. We are planning to use these for flammable
solvents, and reactions involving HCl and NaOH. These hoods will
be used by undergraduates for research also. Any input on the safety
issues involved with these equipments versus the regular hoods would be
appreciated.
-Richard (CHO)

The content of this page reflects the personal opinion(s) of the author(s) only, not the American Chemical Society, ILPI, Safety Emporium, or any other party. Use of any information on this page is at the reader's own risk. Unauthorized reproduction of these materials is prohibited. Send questions/comments about the archive to secretary@dchas.org.The maintenance and hosting of the DCHAS-L archive is provided through the generous support of Safety Emporium.